A. Summary of Prior Art And Information Disclosure Statement
Therapeutic medical devices involving the use of ultrasonic acoustics for the removal of unwanted material from bodily tissue are well known. For example, U.S. Pat. No. 4,808,153 to Parisi suggests that a number of longitudinally vibratory crystals may be mounted in the distal end of an arterial probe. These crystals are secured within a socket of a hollow, beveled-edge tip (which serves as the working element of the probe) so that the vibratory crystals are flush with the tip's outer surface. In use, the entire probe, including the tip containing the vibratory crystals, is inserted into an artery and then moved along the wall of the artery. The vibrating tip therefore emulsifies plaque on the artery's interior wall which is then removed to a patient-external location by vacuum.
U.S. Pat. No. 3,941,122 to Jones discloses a therapeutic ultrasonic probe adapted for use in ophthalmic operations. The end of the probe of Jones '122 consists of a piezoceramic disc which serves to break up the unwanted biological material, which is then aspirated through the probe.
U.S. Pat. No. 3,565,062 to Kuris, and U.S. Pat. No. 4,698,058 to Greenfield et al, both disclose therapeutic ultrasonic probes whereby the piezoceramic elements are located physically outside of the patient during use. Kuris '062 utilizes a tubular member to couple the ultrasonically vibrated piezoceramic element to a distally located working element. Greenfield et al '058, on the other hand, discloses an ultrasonically vibratory wire element.
Attention is also directed to the following U.S. patents which generally disclose therapeutic medical probes using ultrasonic energy whereby a piezoceramic transducer element is located physically outside of the patient during use: U.S. Pat. No. 4,535,759 to Polk et al, U.S. Pat. No. 4,516,398 to Wuchinich et al, U.S. Pat. No. 4,504,264 to Kelman, U.S. Pat. No. 4,063,557 to Wuchinich et al, U.S. Pat. No. 3,352,303 to Delaney, U.S. Pat. No. 4,816,018 to Parisi, U.S. Pat. No. 4,751,916 to Bory, U.S. Pat. No. 4,794,931 to Yock, U.S. Pat. No. 4,561,438 to Bonnett et al, and U.S. Pat. No. 4,223,676 to Wuchinich et al.